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UNITED STATES PATENT OFFICE.

DAVID BROSE, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR OF THREE- FOURTHS TO GEORGE W. MILLER, JOHN J. MCGUIRE, AND GEORGE BROMLEY, ALL OF SAME PLACE.

PROCESS OF MAKING STEEL.

SPECIFICATION forming part of Letters Patent No. 353,247, dated November 23, 1886.

Application filed February 8, 1886. Serial No. 191,219.

To all whom it may concern.-

Be it known that 1, DAVID BROSE, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Process of Making Steel; and I do hereby declare the following to be a full, clear, and exact description thereof.

In the Bessemer process of manufacture ofsteel it is usual, after the charge has been blown in the converter, to add to the molten charge a supply of manganese or spiegeleiseu to effect the recarburization of the metal. This addition is madejust before the casting ofthe charge, either before its removal from the converter or after it has been poured thence into the ladies, and great difficulty has been experienced in causing the proper mixture of the manganese with the metal. The result of an imperfect mixture is a steel uneven in its composition and of lessened utility. Themixing has been effected, generally, by mechanical meanssuch, for example, as by a blast of air, or as describedin the patentof \Villiam Hainsworth, No. 284,006, of August 28, 1888; but such process is unsatisfactory, because it is at best incomplete and entails hard labpr and considerable expense.

I have discovered that the manganese may be mixed with the charge by the addition of limestone thereto either just before or after or simultaneously with the manganese addi- Lion. a violent ebullition and agitation of the metal, which intimately commingles the iron and manganese together, and upon casting the ingots will be found to be homogeneous in their structure. This effect is not produced by the presence of lime in the usual basic lining of the converter.

The result of this treatment is to cause (N0 specimens.)

and manganese in the ladle, and to pour the molten metal from the converter upon it, since in this way the agitation is more thorough and immediate; but I do not desire to limit myself to the time and manner of the treatment, except that it must be done at about the time of introducing the manganese. The use of this process oheapens the manufacture of steel by reason of the fact that it lessens the quantity of manganese which need be cnlploycdto carburize a given charge of metal.

I do not desire to claim, broadly, the use of limestone with molten metal or lime, or limestone and manganese; but limestone has not been heretofore employed for the agitation of the bath of metal, as herein described.

\Vhat I claim as my invention, and desire to secure by Letters Patent, is

1. In the art ofmaking steel, the process of intimately mixing manganese with the refined metal, which consists in adding the manganese and carbonate of lime to the refined metal at or nearly the same time, substantially as and for the purpose specified.

2. In the art of making steel, the process of intimately mixing manganese with the molten 1n.etal,which consists in placing the manganese and carbonate of lime in a ladle and then pour ing the molten metal thereupon, substantially as and for the purpose specified.

In testimony whereof I have hereunto set my hand this 4th day of February, A. D. 1886.

W DAVID BROSE.

\Vituesses:

W. B. OORWIN, THOMAS W. BAKEWELL.

In practice I prefer to place the limestone 4o 

